Respiratory adaptation is the specific change that the

respiratory system The respiratory system (also respiratory apparatus, ventilatory system) is a biological system consisting of specific organs and structures used for gas exchange in animals and plants. The anatomy and physiology that make this happen varies grea ...

undergoes in response to the demands of physical exertion. Intense physical exertion, such as that involved in fitness training, places elevated demands on the respiratory system. Over time, this results in respiratory changes as the system adapts to these requirements. These changes ultimately result in an increased exchange of

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

and

carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...

, which is accompanied by an increase in

metabolism Metabolism (, from ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the co ...

. Respiratory adaptation is a physiological determinant of peak endurance performance, and in elite athletes, the pulmonary system is often a limiting factor to exercise under certain conditions.

Neural control

Respiratory adaptation begins almost immediately after the initiation of the physical stress associated with exercise. This triggers signals from the

motor cortex The motor cortex is the region of the cerebral cortex involved in the planning, motor control, control, and execution of voluntary movements. The motor cortex is an area of the frontal lobe located in the posterior precentral gyrus immediately ...

that stimulate the respiratory center of the

brain stem The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is co ...

, in conjunction with feedback from the proprioreceptors in the muscles and joints of the active limbs.

Breathing rate

With higher intensity training, breathing rate is increased in order to allow more air to move in and out of the lungs, which enhances gas exchange. Endurance training typically results in an increase in the respiration rate.

Lung capacity

With adaptation, lung capacity increases, allowing a greater quantity of air to move in and out. Endurance training typically results in an increase in

tidal volume Tidal is the adjectival form of tide. Tidal may also refer to: * ''Tidal'' (album), a 1996 album by Fiona Apple * Tidal (king), a king involved in the Battle of the Vale of Siddim * TidalCycles TidalCycles (also known as Tidal) is a live coding ...

Respiratory muscles

Muscles involved in respiration, including the diaphragm and

intercostal muscles The intercostal muscles comprise many different groups of muscles that run between the ribs, and help form and move the chest wall. The intercostal muscles are mainly involved in the mechanical aspect of breathing by helping expand and shrink th ...

, increase in strength and endurance. This results in an improved ability to breathe in more air, for longer amounts of time with less fatigue. Aerobic training typically improves the endurance of respiratory muscles, whereas anaerobic training tends to increase the size and strength of respiratory muscles.

Lung capillaries

Exercise increases the vascularization of the lungs. This allows the more blood flow in and out of the lungs. This enhances the uptake of oxygen, since there is greater surface area for blood to bind with

haemoglobin Hemoglobin (haemoglobin, Hb or Hgb) is a protein containing iron that facilitates the transportation of oxygen in red blood cells. Almost all vertebrates contain hemoglobin, with the sole exception of the fish family Channichthyidae. Hemoglobi ...

Alveoli

Respiratory adaptation results an increase in the number of alveoli, which enables more gas exchange to occur. This is coupled with an increase in alveolar oxygen tension.

References

{{Reflist Respiratory physiology Exercise physiology